Driving part for variable-capacity compressor

ABSTRACT

The drive unit has an effect of maintaining controllability and preventing a hunting problem caused under low flow conditions since it includes a friction ring module.

TECHNICAL FIELD

The present invention relates to a drive unit for a variable capacitycompressor, and more particularly, to a drive unit for a variablecapacity compressor, which has a simplified structure.

BACKGROUND ART

In general, a compressor applied to air conditioning systems sucksrefrigerant gas having passed through an evaporator to compress the sameto high temperature and high pressure, and then discharges thecompressed refrigerant gas to a condenser. As this compressor, there areused various types of compressors such as a reciprocating compressor, arotary compressor, a scroll compressor, and a swash plate compressor.

The swash plate compressor includes a disc-shaped swash plate that isobliquely installed to a drive shaft rotated by power transmitted froman engine to be rotated by the drive shaft. In addition, the principleof the swash plate compressor is to suck or compress and dischargerefrigerant gas by rectilinearly reciprocating a plurality of pistonswithin cylinders along with the rotation of the swash plate. By way ofexample, a variable capacity-type swash plate compressor disclosed inKorean Patent Application Publication No. 2012-0100189 includes a swashplate, which is installed to a drive shaft and has an angle ofinclination varied with the thermal load, in order to regulate thedischarge rate of refrigerant in such a manner that the feed rates ofpistons are changed while the angle of inclination of the swash plate isvaried.

Typically, a drive unit for a conventional variable capacity-type swashplate compressor has a structure in which a hinge pin fixedly positionedto a hub slides relative to a rotor fixed to a rotary shaft to adjust anangle of inclination of a swash plate through a shaft bush sliding aboutthe rotary shaft.

However, this hinge mechanism requires the process of press-fitting therotor to the rotary shaft, thereby causing complexity of work processesand product structures. Hence, the drive unit is disadvantageous interms of weight, process, or price competitiveness. In addition, thedrive unit is disadvantageous in that the gap between components isrelatively large due to the clearance of the high mechanism.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made in view of theabove-mentioned problems, and an object thereof is to provide a driveunit for a variable capacity compressor, which has a simplifiedstructure.

Technical Solution

In accordance with one aspect of the present invention, a drive unit fora variable capacity compressor includes a drive shaft (100), one end ofwhich is connected to a pulley of an engine, so that a driving force istransmitted from the engine to the drive shaft (100), a support balance(300) coupled to a pulley-side end of the drive shaft (100) to support athrust bearing, a swash plate (500) spaced apart from the supportbalance (300) and allowing a discharge rate and a pressure ofrefrigerant to be regulated according to an angle of inclination of theswash plate (500), a hinge part (700) configured to connect the supportbalance (300) to the swash plate (500) and transmit a rotational forceof the drive shaft (100) to the swash plate (500), and a friction ringmodule configured to control the angle of inclination of the swash plate(500) under low flow conditions by a frictional force generated betweenthe drive shaft (100) and the friction ring module.

The friction ring module may include a polygonal pipe-shaped ring body(1000) fitted to the drive shaft (100) in its longitudinal direction,and a support spring (1100) fitted onto the ring body (1000).

Alternatively, the friction ring module may include a cylindrical ringbody (1000 a) fitted to the drive shaft (100) in its longitudinaldirection, and a support spring (1100) fitted onto the ring body (1000a).

The ring body (1000, 1000 a) may have an inner diameter smaller than anouter diameter of the drive shaft (100).

The ring body (1000, 1000 a) may have an opening (1002, 1002 a) formedin its longitudinal direction.

The drive unit may further include a circular or semicircular retainer(1300) disposed at one side of the drive shaft (100) facing theconnected pulley to restrict movement of the friction ring module.

The ring body (1000, 1000 a) may include a plurality of hooks (1004,1004 a) extending outward from one end thereof facing the swash plate(500) and bent toward the retainer (1300).

The support spring (1100) may be inserted between the hooks (1004, 1004a) and the ring body (1000, 1000 a).

The support spring (1100) may have an inner diameter greater than anouter diameter of the ring body (1000, 1000 a).

A distance between the ring body (1000, 1000 a) and each of the hooks(1004, 1004 a) may be larger than a thickness of the support spring(1100).

The ring body (1000, 1000 a) may move along the drive shaft (100) whenthe angle of inclination of the swash plate (500) is changed, and bestopped by coming into contact with the retainer (1300) when the swashplate (500) is inclined at a minimum angle.

The ring body (1000 a) may have a plurality of friction protrusions(1006 a) protruding from its inner peripheral surface to the drive shaft(100).

In accordance with another aspect of the present invention, in avariable capacity compressor includes a drive shaft (100) rotatablysupported in a housing and a swash plate (500) allowing a discharge rateof refrigerant to be variably controlled according to an angle ofinclination of the swash plate (500) while a driving force transmittedto the drive shaft (100) is transmitted to the swash plate (500), thevariable capacity compressor includes a friction member (1000, 1000 a)coupled to the drive shaft (100) to be axially movable, positionedbetween the swash plate (500) and a support spring (1100) for applying aforce in a direction of increasing the angle of inclination of the swashplate in an initial stage of operation, and configured to have acentrifugal force, wherein the friction member (1000, 1000 a) restrictsa rapid change in the angle of inclination of the swash plate (500)under low flow conditions by a frictional force generated between thefriction member (1000, 1000 a) and the drive shaft (100).

The friction member (1000, 1000 a) may be modularized with the supportspring (1100) to be axially coupled to the drive shaft (100).

Advantageous Effects

A drive unit for a variable capacity compressor according to exemplaryembodiments of the present invention has an effect of maintainingcontrollability and also preventing a hunting problem caused under lowflow conditions since it includes a friction ring module.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an assembled perspective view illustrating a drive unit for avariable capacity compressor at a maximum angle of inclination accordingto an embodiment of the present invention.

FIG. 2 is an exploded perspective view illustrating the drive unit for avariable capacity compressor according to FIG. 1.

FIG. 3 is a perspective view illustrating a friction ring of the driveunit for a variable capacity compressor according to FIG. 1.

FIG. 4 is a perspective view illustrating a friction ring of a driveunit for a variable capacity compressor according to another embodimentof the present invention.

FIG. 5 is a top view illustrating a coupled state of the friction ringaccording to FIG. 4.

BEST MODE FOR INVENTION

Hereinafter, a drive unit for a variable capacity compressor accordingto exemplary embodiments of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1 is an assembled perspective view illustrating a drive unit for avariable capacity compressor at a maximum angle of inclination accordingto an embodiment of the present invention. FIG. 2 is an explodedperspective view illustrating the drive unit for a variable capacitycompressor according to FIG. 1. FIG. 3 is a perspective viewillustrating a friction ring of the drive unit for a variable capacitycompressor according to FIG. 1.

As illustrated in FIGS. 1 and 2, the drive unit for a variable capacitycompressor, which is designated by reference numeral 10, according tothe embodiment of the present invention is inserted into a compressorconsisting of a cylinder block and front and rear housings. The driveunit 10 includes a pulley (not shown) that is powered by an engine, adrive shaft 100 that is coupled to the pulley to be rotated by thepulley, and a support balance 300 and a swash plate 500 that are coupledto the drive shaft. The support balance 300 and the swash plate 500 areinterconnected by a hinge part 700. A coil spring 910 and a bush 900 arecoupled between the swash plate 500 and the drive shaft 100 to helpinitially operate the swash plate 500. The drive unit 10 includes afriction ring module that is formed at the opposite end of the pulleyconnection portion of the drive shaft 100, thereby maintainingcontrollability and also preventing hunting under low flow conditions.

One end of the drive shaft 100 is connected to the pulley to berotatably supported by the front housing, and the other end thereof isrotatably supported by the rear housing. The drive shaft 100 has a hingeconnection portion 110 that is in contact with the support balance 300.

The hinge connection portion 110 serves to prevent the support balance300 from moving to the swash plate 500 while connecting the hinge part700 to the drive shaft 100. To this end, the hinge connection portion110 has a through-hole that is formed through the drive shaft 100 in thedirection leading both ends of a counter weight 330 of the supportbalance 300 in FIG. 1 (the direction is defined on the basis of thesupport balance since the support balance is fixedly coupled to thedrive shaft so as not to rotate for itself). The through-bole formed inthe hinge connection portion 110 may affect the stiffness of the driveshaft 100. Therefore, it is preferable to prevent a reduction instiffness of the drive shaft 100 by reinforcing the thickness of thedrive shaft 100 in the vicinity of the through-hole. Accordingly, thehinge connection portion 110 is formed to protrude outward from theouter peripheral surface of the drive shaft 100.

The support balance 300 is coupled to the pulley-side end of the driveshaft 100, and the swash plate 500 is fitted to the drive shaft 100 inthe state in which the swash plate 500 is spaced apart from the supportbalance 300 by a predetermined distance.

The support balance 300 is substituted for a conventional rotor formedintegrally with lug plates, and serves to support a thrust bearing (notshown). The conventional rotor is disposed opposite to the swash platein order to transmit rotational force to the swash plate and balance thedrive unit (static balance function) since yawing is generated due toimbalance of weight when a mass is provided on the drive shaft 100.Although the conventional rotor formed integrally with lug plates isperformed for the above functions, it is difficult to reduce the size ofthe drive unit due to the large size and weight of the rotor and thecomplicated hinge structure. In addition, the drive shaft 100 or theperipheral parts thereof may be deformed in the process of press-fittingthe rotor to the drive shaft 100. Accordingly, the present invention isintended to propose the support balance 300 as a substitute for therotor.

The support balance 300 includes a disc-shaped bearing support 310, astepped portion 312 that protrudes toward the connected pulley and has asmaller diameter than the bearing support 310, and a ring-shaped counterweight 330 that is provided on one side of the outer peripheral surfaceof the bearing support 310 and has a greater radius than the bearingsupport 310.

The stepped portion 312 is formed integrally with the bearing support310, and each of the bearing support 310 and the stepped portion 312 hasa hollow formed at the center thereof for insertion of the drive shaft100.

The counter weight 330 is preferably disposed at the lower side of thebearing support 310 in the arrangement of the drive unit illustrated inFIGS. 1 and 2. The support balance 300 has an eccentric load by theone-sided counter weight 330 thereto. The counter weight 330 serves toprevent an eccentricity of weight due to the structure of the hinge part700 for adjusting the angle of the swash plate, and is thus disposedopposite to the weighted portion of the swash plate 500 and the hingepart 700.

Unlike the conventional rotor coupled by press-fit, the support balance300 has an eccentric structure at the hollow thereof into which thedrive shaft 100 is inserted. Thus, the support balance 300 is maintainedin the coupled state without rotating on the drive shaft 100.

The swash plate 500 is connected to a piston (not shown) inserted into acylinder bore formed in the cylinder block. The piston reciprocates inthe cylinder bore along with the rotation of the swash plate 500 tothereby suck refrigerant or compress the refrigerant in the cylinderbore. The discharge rate and pressure of the refrigerant is regulated byadjusting the angle of inclination of the swash plate 500.

The swash plate 500 has a swash plate arm 510 and a hub 530 thatprotrude from the flat surface thereof facing the support balance 300.The swash plate arm 510 is relatively disposed at the upper side of theswash plate 500 whereas the hub 530 is relatively disposed at the lowerside of the swash plate 500 in the state in which the hub 530 is spacedapart from the swash plate arm 510, in FIGS. 1 and 2.

The swash plate arm 510 consists of a pair of swash plate arms that faceeach other and are made of a sheet of metal, and the swash plate arms510 have respective through-holes formed therein for insertion of asecond hinge pin 770 to be described later. The hinge part 700 isinserted between the swash plate arms 510 to be rotatably coupled to theswash plate arms 510 by the second hinge pin 770.

The hub 530 has a substantially semi-cylindrical shape, and protrudesfurther than the swash plate arms 510 toward the support balance 300.The hub 530 serves to restrict the movement of the swash plate 500 suchthat the swash plate 500 is not inclined above a predetermined anglewhen the angle of inclination of the swash plate 500 is adjusted. Tothis end, the hub 530 preferably protrudes enough to come into contactwith the support balance 300 when the swash plate 500 is inclined at amaximum angle.

The support balance 300 is connected to the swash plate 500 by the hingepart 700.

The hinge part 700 includes a pair of first hinge arms 710 disposed atboth sides of the hinge connection portion 110 of the drive shaft 100, asecond hinge arm 730 protruding toward the swash plate arms 510, a firsthinge pin 750 coupled to the first hinge arms 710, and a second hingepin 770 coupled to the second hinge arm 730.

The first hinge arms 710 are connected to the second hinge arm 730. Thefirst hinge arms 710 face each other and are made of a sheet of metal.The first hinge arms 710 grasp the hinge connection portion 110 at bothsides thereof and have respective through-holes formed therein forinsertion of the first hinge pin 750, in FIG. 3. The first hinge pin 750is coupled to the first hinge arms 710 by passing through thethrough-hole of the hinge connection portion 110 through one of thefirst hinge arms 710 and then passing through the other of the firsthinge arms 710. The first hinge arms 710 are rotatably coupled to thehinge connection portion 110 by the first hinge pin 750. If the hingeconnection portion 110 has a curved outer peripheral surface accordingto the shape of the outer peripheral surface of the drive shaft 100, thehinge connection portion 110 does not come into surface contact with thefirst hinge arms 710 but a gap is formed therebetween. Thus, the contactsurface of the hinge connection portion 110 coming into contact with thefirst hinge arms 710 is preferably flat rather than curved such that thefirst hinge arms 710 are able to stably grasp the hinge connectionportion 110.

The second hinge arm 730 has a thickness corresponding to the distancebetween the pair of swash plate arms 510, and has a through-hole formedtherein for insertion of the second hinge pin 770. The second hinge pin770 is inserted into one of the swash plate arms 510, passes through thesecond hinge arm 730, and is then inserted into the other facing swashplate arm 510. The swash plate arms 510 are rotatably coupled to thesecond hinge arm 730 by the second hinge pin 770.

As illustrated in FIG. 2, the bush 900 has a cylindrical shape and isinserted between the swash plate 500 and the drive shaft 100. The coilspring 910 is inserted between the bush 900 and the drive shaft 100. Thebush 900 is elastically supported by the coil spring 910 and slidesalong the drive shaft 100. The bush 900 slides together with the swashplate 500 when the angle of inclination of the swash plate 500 ischanged, with the consequence that the swash plate 500 is smoothlymovable along the drive shaft 100.

Meanwhile, the friction ring module is provided to prevent a huntingphenomenon in which noise occurs when the angle of the swash plate isnot maintained small due to too low friction under low flow conditions.

As illustrated in FIGS. 2 and 3, the friction ring module includes aring body 1000 and a support spring 1100. A retainer 1300 is fitted tothe opposite end of the pulley connection portion of the drive shaft 100to restrict the movement of the friction ring module. The retainer 1300has a circular or semicircular ring shape, and serves as a stopper.

The ring body 1000 has a polygonal pipe shape. A portion of the ringbody 1000 is cut to form an opening 1002, and the ring body 1000 isfitted to the drive shaft 100 in the longitudinal direction thereof.Since the ring body 1000 is not cylindrical, the ring body 1000 iscoupled to the drive shaft 100 with a gap therebetween in some sectionswithout entirely surrounding the outer peripheral surface of the driveshaft 100. The opening 1002 is formed in the longitudinal direction ofthe drive shaft 100. Preferably, the ring body 1000 has an innerdiameter smaller than the outer diameter of the drive shaft 100 in thestate in which the opening 1002 is not formed in the ring body 1000.This is to generate a force in the central direction of the drive shaft100 and thus generate a frictional force between the ring body 1000 andthe drive shaft 100. There is no problem in the assembly of the ringbody 1000 because the ring body 1000 has the opening 1002 even thoughthe inner diameter of the ring body 1000 is smaller than the outerdiameter of the drive shaft 100. The ring body 1000 has a plurality ofhooks 1004 formed at one end thereof facing the swash plate 500 so thatthe support spring 1100 is coupled to the hooks 1004.

The hooks 1004 extend outward from one end of the ring body 1000 facingthe swash plate 500 and are bent toward the retainer 1300. Preferably,the distance between each of the hooks 1004 and the outer peripheralsurface of the ring body 1000 is larger than the thickness of thesupport spring 1100 so as not to interfere with the operation of thesupport spring 1100. The support spring 1100 is inserted between thehooks 1004 and the ring body 1000.

One end of the support spring 1100 is inserted between the hooks 1004and the ring body 1000, and the other end thereof extends toward theretainer 1300. The support spring 1100 has an inner diameter slightlygreater than the outer diameter of the ring body 1000.

The reason that the hooks 1004 are formed in the ring body 1000 despitethe greater inner diameter of the support spring 1100 than the outerdiameter of the ring body 1000 is to smoothly assemble the supportspring 1100. That is, the hooks 1004 serve to temporarily fix thesupport spring 1100 in the assembly thereof to prevent the supportspring 1100 from moving to the swash plate 500. However, the hooks 1004does not interfere with the movement of the support spring 1100 to theretainer 1300.

As illustrated in FIGS. 4 and 5, a friction ring module of a drive unitaccording to another embodiment of the present invention includes acylindrical ring body 1000 a having an opening 1002 a formed at one sidethereof. The ring body 1000 a has a plurality of hooks 1004 a formed onthe outer peripheral surface thereof, and may further have a pluralityof friction protrusions 1006 a protruding from the inner peripheralsurface thereof to the drive shaft 100 (the same components as those ofthe previous embodiment will not be described in detail).

The friction protrusions 1006 a serve to increase a frictional forcebetween the drive shaft 100 and the ring body 1000 a, and to increase aforce generated in the central direction of the drive shaft 100, asillustrated in FIG. 5.

The shape of the ring body 1000 a is not restricted. However, in thecase where the ring body 1000 a is configured to have a cylindricalshape and support the drive shaft 100 at three points by the frictionprotrusions 1006 a and uses a multiple press as in the presentembodiment, it is possible to enhance productivity.

If the frictional force is too high, there is a problem in that pressuredoes not change at all due to fixation of the friction ring module tothe drive shaft 100. On the other hand, if the frictional force is toolow, there is a problem in that noise occurs (hunting) since it isdifficult to keep the angle of the swash plate small under low loadconditions.

In the present invention, the ring body 1000 a has an inner diametersmaller than the outer diameter of the drive shaft 100 or has thefriction protrusions 1006 a to properly maintain the frictional force.Therefore, the drive unit has an effect of maintaining controllabilityand also preventing hunting under low flow conditions.

In the above-mentioned embodiments, the ring body 1000 or 1000 a movesbetween the bush 900 and the retainer 1300 that are inserted between theswash plate 500 and the drive shaft 100, and the movement of the ringbody is stopped while the ring body is pushed by the bush 900 at theminimum angle of the swash plate 500 to come into contact with theretainer 1300. Accordingly, the length of the ring body 1000 or 1000 ain the longitudinal direction of the drive shaft 100 is varied dependingon the position of the retainer 1300 when the swash plate 500 isinclined at a minimum angle.

Meanwhile, the ring body 1000 may be coupled to the drive shaft 100 tobe axially movable, may be positioned between the swash plate 500 andthe support spring 1100 for applying a force in the direction ofincreasing the angle of inclination of the swash plate in the initialstage of operation, and may be configured to have a centrifugal force.Thus, since the ring body 1000 serves to restrict a rapid change in theangle of inclination of the swash plate 500 under low flow conditions bythe frictional force generated between the ring body 1000 and the driveshaft 100, the ring body 1000 may be defined as a friction member. Inaddition, the ring body 1000 may be modularized with the support spring1100 to be axially coupled to the drive shaft 100.

Since the drive unit includes the friction ring module having theabove-mentioned structure, it is possible to maintain controllabilityand prevent a hunting problem caused under low flow conditions.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a drive unit for a variablecapacity compressor, which has a simplified structure.

1.-14. (canceled)
 15. A drive unit for a variable capacity compressor,comprising: a drive shaft, one end of which is connected to a pulley ofan engine, so that a driving force is transmitted from the engine to thedrive shaft; a support balance coupled to a pulley-side end of the driveshaft to support a thrust bearing; a swash plate spaced apart from thesupport balance and allowing a discharge rate and a pressure ofrefrigerant to be regulated according to an angle of inclination of theswash plate; a hinge part configured to connect the support balance tothe swash plate and transmit a rotational force of the drive shaft tothe swash plate; and a friction ring module configured to control theangle of inclination of the swash plate under low flow conditions by africtional force generated between the drive shaft and the friction ringmodule.
 16. The drive unit according to claim 15, wherein the frictionring module comprises a ring body fitted to the drive shaft in itslongitudinal direction, and a support spring fitted onto the ring body.17. The drive unit according to claim 16, wherein the ring body ispolygonal pipe shape or cylindrical shape.
 18. The drive unit accordingto claim 16, wherein the ring body has an inner diameter smaller than anouter diameter of the drive shaft.
 19. The drive unit according to claim16, wherein the ring body has an opening formed in its longitudinaldirection.
 20. The drive unit according to claim 16, further comprisinga circular or semicircular retainer disposed at one side of the driveshaft facing the connected pulley to restrict movement of the frictionring module.
 21. The drive unit according to claim 20, wherein the ringbody comprises a plurality of hooks extending outward from one endthereof facing the swash plate and bent toward the retainer.
 22. Thedrive unit according to claim 21, wherein the support spring is insertedbetween the hooks and the ring body.
 23. The drive unit according toclaim 22, wherein a distance between the ring body and each of the hooksis larger than a thickness of the support spring
 24. The drive unitaccording to claim 16, wherein the support spring has an inner diametergreater than an outer diameter of the ring body.
 25. The drive unitaccording to claim 20, wherein the ring body moves along the drive shaftwhen the angle of inclination of the swash plate is changed, and isstopped by coming into contact with the retainer when the swash plate isinclined at a minimum angle.
 26. The drive unit according to claim 16,wherein the ring body has a plurality of friction protrusions protrudingfrom its inner peripheral surface to the drive shaft.
 27. A variablecapacity compressor, which comprises a drive shaft rotatably supportedin a housing and a swash plate allowing a discharge rate of refrigerantto be variably controlled according to an angle of inclination of theswash plate while a driving force transmitted to the drive shaft istransmitted to the swash plate, the variable capacity compressorcomprising: a friction member coupled to the drive shaft to be axiallymovable, positioned between the swash plate and a support spring forapplying a force in a direction of increasing the angle of inclinationof the swash plate in an initial stage of operation, and configured tohave a centrifugal force, wherein the friction member restricts a rapidchange in the angle of inclination of the swash plate under low flowconditions by a frictional force generated between the friction memberand the drive shaft
 28. The variable capacity compressor according toclaim 27, wherein the friction member is modularized with the supportspring to be axially coupled to the drive shaft.